// This file is a part of Julia. License is MIT: https://julialang.org/license // Meant to be included in #ifndef JL_THREADS_H #define JL_THREADS_H #include // threading ------------------------------------------------------------------ // WARNING: Threading support is incomplete and experimental // Nonetheless, we define JL_THREAD and use it to give advanced notice to // maintainers of what eventual threading support will change. // JULIA_ENABLE_THREADING is switched on in Make.inc if JULIA_THREADS is // set (in Make.user) // Options for task switching algorithm (in order of preference): // JL_HAVE_ASM -- mostly setjmp // JL_HAVE_UNW_CONTEXT -- hybrid of libunwind for start, setjmp for resume // JL_HAVE_UCONTEXT -- posix standard API, requires syscall for resume // JL_HAVE_SIGALTSTACK -- requires several syscall for start, setjmp for resume #ifdef _OS_WINDOWS_ #define JL_HAVE_UCONTEXT typedef win32_ucontext_t jl_ucontext_t; #else #if !defined(JL_HAVE_UCONTEXT) && \ !defined(JL_HAVE_ASM) && \ !defined(JL_HAVE_UNW_CONTEXT) && \ !defined(JL_HAVE_SIGALTSTACK) #if (defined(_CPU_X86_64_) || defined(_CPU_X86_) || defined(_CPU_AARCH64_) || \ defined(_CPU_ARM_) || defined(_CPU_PPC64_)) #define JL_HAVE_ASM #elif defined(_OS_DARWIN_) #define JL_HAVE_UNW_CONTEXT #elif defined(_OS_LINUX_) #define JL_HAVE_UCONTEXT #else #define JL_HAVE_UNW_CONTEXT #endif #endif #if defined(JL_HAVE_ASM) || defined(JL_HAVE_SIGALTSTACK) typedef struct { jl_jmp_buf uc_mcontext; } jl_ucontext_t; #endif #if defined(JL_HAVE_UCONTEXT) || defined(JL_HAVE_UNW_CONTEXT) #define UNW_LOCAL_ONLY #include typedef ucontext_t jl_ucontext_t; #endif #endif // Recursive spin lock typedef struct { volatile unsigned long owner; uint32_t count; } jl_mutex_t; typedef struct { jl_taggedvalue_t *freelist; // root of list of free objects jl_taggedvalue_t *newpages; // root of list of chunks of free objects uint16_t osize; // size of objects in this pool } jl_gc_pool_t; typedef struct { int64_t allocd; int64_t freed; uint64_t malloc; uint64_t realloc; uint64_t poolalloc; uint64_t bigalloc; uint64_t freecall; } jl_thread_gc_num_t; typedef struct { // variable for tracking weak references arraylist_t weak_refs; // live tasks started on this thread // that are holding onto a stack from the pool arraylist_t live_tasks; // variables for tracking malloc'd arrays struct _mallocarray_t *mallocarrays; struct _mallocarray_t *mafreelist; // variables for tracking big objects struct _bigval_t *big_objects; // variables for tracking "remembered set" arraylist_t rem_bindings; arraylist_t _remset[2]; // contains jl_value_t* // lower bound of the number of pointers inside remembered values int remset_nptr; arraylist_t *remset; arraylist_t *last_remset; // variables for allocating objects from pools #ifdef _P64 # define JL_GC_N_POOLS 41 #elif MAX_ALIGN == 8 # define JL_GC_N_POOLS 42 #else # define JL_GC_N_POOLS 43 #endif jl_gc_pool_t norm_pools[JL_GC_N_POOLS]; #define JL_N_STACK_POOLS 16 arraylist_t free_stacks[JL_N_STACK_POOLS]; } jl_thread_heap_t; // Cache of thread local change to global metadata during GC // This is sync'd after marking. typedef union _jl_gc_mark_data jl_gc_mark_data_t; typedef struct { void **pc; // Current stack address for the pc (up growing) jl_gc_mark_data_t *data; // Current stack address for the data (up growing) void **pc_start; // Cached value of `gc_cache->pc_stack` void **pc_end; // Cached value of `gc_cache->pc_stack_end` } jl_gc_mark_sp_t; typedef struct { // thread local increment of `perm_scanned_bytes` size_t perm_scanned_bytes; // thread local increment of `scanned_bytes` size_t scanned_bytes; // Number of queued big objects (<= 1024) size_t nbig_obj; // Array of queued big objects to be moved between the young list // and the old list. // A set low bit means that the object should be moved from the old list // to the young list (`mark_reset_age`). // Objects can only be put into this list when the mark bit is flipped to // `1` (atomically). Combining with the sync after marking, // this makes sure that a single objects can only appear once in // the lists (the mark bit cannot be flipped to `0` without sweeping) void *big_obj[1024]; jl_mutex_t stack_lock; void **pc_stack; void **pc_stack_end; jl_gc_mark_data_t *data_stack; } jl_gc_mark_cache_t; typedef struct _jl_excstack_t jl_excstack_t; // This includes all the thread local states we care about for a thread. // Changes to TLS field types must be reflected in codegen. #define JL_MAX_BT_SIZE 80000 struct _jl_tls_states_t { struct _jl_gcframe_t *pgcstack; size_t world_age; int16_t tid; uint64_t rngseed; volatile size_t *safepoint; volatile int8_t sleep_check_state; // Whether it is safe to execute GC at the same time. #define JL_GC_STATE_WAITING 1 // gc_state = 1 means the thread is doing GC or is waiting for the GC to // finish. #define JL_GC_STATE_SAFE 2 // gc_state = 2 means the thread is running unmanaged code that can be // execute at the same time with the GC. volatile int8_t gc_state; volatile int8_t in_finalizer; int8_t disable_gc; jl_thread_heap_t heap; jl_thread_gc_num_t gc_num; uv_mutex_t sleep_lock; uv_cond_t wake_signal; volatile sig_atomic_t defer_signal; struct _jl_task_t *current_task; #ifdef MIGRATE_TASKS struct _jl_task_t *previous_task; #endif struct _jl_task_t *root_task; void *stackbase; size_t stacksize; jl_ucontext_t base_ctx; // base context of stack jl_jmp_buf *safe_restore; // Temp storage for exception thrown in signal handler. Not rooted. struct _jl_value_t *sig_exception; // Temporary backtrace buffer. Scanned for gc roots when bt_size > 0. uintptr_t *bt_data; // JL_MAX_BT_SIZE + 1 elements long size_t bt_size; // Size for backtrace in transit in bt_data // Atomically set by the sender, reset by the handler. volatile sig_atomic_t signal_request; // Allow the sigint to be raised asynchronously // this is limited to the few places we do synchronous IO // we can make this more general (similar to defer_signal) if necessary volatile sig_atomic_t io_wait; #ifndef _OS_WINDOWS_ // These are only used on unix now pthread_t system_id; void *signal_stack; #endif #ifdef _OS_WINDOWS_ int needs_resetstkoflw; #endif // execution of certain certain impure // statements is prohibited from certain // callbacks (such as generated functions) // as it may make compilation undecidable int in_pure_callback; // Counter to disable finalizer **on the current thread** int finalizers_inhibited; arraylist_t finalizers; jl_gc_mark_cache_t gc_cache; arraylist_t sweep_objs; jl_gc_mark_sp_t gc_mark_sp; // Saved exception for previous external API call or NULL if cleared. // Access via jl_exception_occurred(). struct _jl_value_t *previous_exception; }; // Update codegen version in `ccall.cpp` after changing either `pause` or `wake` #ifdef __MIC__ # define jl_cpu_pause() _mm_delay_64(100) # define jl_cpu_wake() ((void)0) # define JL_CPU_WAKE_NOOP 1 #elif defined(_CPU_X86_64_) || defined(_CPU_X86_) /* !__MIC__ */ # define jl_cpu_pause() _mm_pause() # define jl_cpu_wake() ((void)0) # define JL_CPU_WAKE_NOOP 1 #elif defined(_CPU_AARCH64_) || (defined(_CPU_ARM_) && __ARM_ARCH >= 7) # define jl_cpu_pause() __asm__ volatile ("wfe" ::: "memory") # define jl_cpu_wake() __asm__ volatile ("sev" ::: "memory") # define JL_CPU_WAKE_NOOP 0 #else # define jl_cpu_pause() ((void)0) # define jl_cpu_wake() ((void)0) # define JL_CPU_WAKE_NOOP 1 #endif #ifdef __cplusplus extern "C" { #endif JL_DLLEXPORT void (jl_cpu_pause)(void); JL_DLLEXPORT void (jl_cpu_wake)(void); // gc safepoint and gc states // This triggers a SegFault when we are in GC // Assign it to a variable to make sure the compiler emit the load // and to avoid Clang warning for -Wunused-volatile-lvalue #define jl_gc_safepoint_(ptls) do { \ jl_signal_fence(); \ size_t safepoint_load = *ptls->safepoint; \ jl_signal_fence(); \ (void)safepoint_load; \ } while (0) #ifdef __clang_analyzer__ // This is a sigint safepoint, not a GC safepoint (which // JL_NOTSAFEPOINT refers to) void jl_sigint_safepoint(jl_ptls_t tls) JL_NOTSAFEPOINT; #else #define jl_sigint_safepoint(ptls) do { \ jl_signal_fence(); \ size_t safepoint_load = ptls->safepoint[-1]; \ jl_signal_fence(); \ (void)safepoint_load; \ } while (0) #endif #ifndef JULIA_ENABLE_THREADING #define jl_gc_state(ptls) ((int8_t)0) STATIC_INLINE int8_t jl_gc_state_set(jl_ptls_t ptls, int8_t state, int8_t old_state) { (void)ptls; (void)state; return old_state; } #else // ifndef JULIA_ENABLE_THREADING // Make sure jl_gc_state() is always a rvalue #define jl_gc_state(ptls) ((int8_t)ptls->gc_state) STATIC_INLINE int8_t jl_gc_state_set(jl_ptls_t ptls, int8_t state, int8_t old_state) { ptls->gc_state = state; // A safe point is required if we transition from GC-safe region to // non GC-safe region. if (old_state && !state) jl_gc_safepoint_(ptls); return old_state; } #endif // ifndef JULIA_ENABLE_THREADING STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, int8_t state) { return jl_gc_state_set(ptls, state, jl_gc_state(ptls)); } #ifdef __clang_analyzer__ int8_t jl_gc_unsafe_enter(jl_ptls_t ptls); // Can be a safepoint int8_t jl_gc_unsafe_leave(jl_ptls_t ptls, int8_t state) JL_NOTSAFEPOINT; int8_t jl_gc_safe_enter(jl_ptls_t ptls) JL_NOTSAFEPOINT; int8_t jl_gc_safe_leave(jl_ptls_t ptls, int8_t state); // Can be a safepoint #else #define jl_gc_unsafe_enter(ptls) jl_gc_state_save_and_set(ptls, 0) #define jl_gc_unsafe_leave(ptls, state) ((void)jl_gc_state_set(ptls, (state), 0)) #define jl_gc_safe_enter(ptls) jl_gc_state_save_and_set(ptls, JL_GC_STATE_SAFE) #define jl_gc_safe_leave(ptls, state) ((void)jl_gc_state_set(ptls, (state), JL_GC_STATE_SAFE)) #endif JL_DLLEXPORT void (jl_gc_safepoint)(void); JL_DLLEXPORT void jl_gc_enable_finalizers(jl_ptls_t ptls, int on); JL_DLLEXPORT void jl_wakeup_thread(int16_t tid); #ifdef __cplusplus } #endif #endif